In order to quantify the overall time spent in the PSCI software
implementation, an initial collection of PMF instrumentation points
has been added.
Instrumentation has been added to the following code paths:
- Entry to PSCI SMC handler. The timestamp is captured as early
as possible during the runtime exception and stored in memory
before entering the PSCI SMC handler.
- Exit from PSCI SMC handler. The timestamp is captured after
normal return from the PSCI SMC handler or if a low power state
was requested it is captured in the bl31 warm boot path before
return to normal world.
- Entry to low power state. The timestamp is captured before entry
to a low power state which implies either standby or power down.
As these power states are mutually exclusive, only one timestamp
is defined to describe both. It is possible to differentiate between
the two power states using the PSCI STAT interface.
- Exit from low power state. The timestamp is captured after a standby
or power up operation has completed.
To calculate the number of cycles spent running code in Trusted Firmware
one can perform the following calculation:
(exit_psci - enter_psci) - (exit_low_pwr - enter_low_pwr).
The resulting number of cycles can be converted to time given the
frequency of the counter.
Change-Id: Ie3b8f3d16409b6703747093b3a2d5c7429ad0166
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>
This patch moves the PSCI services and BL31 frameworks like context
management and per-cpu data into new library components `PSCI` and
`el3_runtime` respectively. This enables PSCI to be built independently from
BL31. A new `psci_lib.mk` makefile is introduced which adds the relevant
PSCI library sources and gets included by `bl31.mk`. Other changes which
are done as part of this patch are:
* The runtime services framework is now moved to the `common/` folder to
enable reuse.
* The `asm_macros.S` and `assert_macros.S` helpers are moved to architecture
specific folder.
* The `plat_psci_common.c` is moved from the `plat/common/aarch64/` folder
to `plat/common` folder. The original file location now has a stub which
just includes the file from new location to maintain platform compatibility.
Most of the changes wouldn't affect platform builds as they just involve
changes to the generic bl1.mk and bl31.mk makefiles.
NOTE: THE `plat_psci_common.c` FILE HAS MOVED LOCATION AND THE STUB FILE AT
THE ORIGINAL LOCATION IS NOW DEPRECATED. PLATFORMS SHOULD MODIFY THEIR
MAKEFILES TO INCLUDE THE FILE FROM THE NEW LOCATION.
Change-Id: I6bd87d5b59424995c6a65ef8076d4fda91ad5e86
dp-arm
Soby Mathew